Yes! This bug was already fixed a long time ago, but it came back.

If you double click in the survival part of the creative inventory it doesn't stack all items on the cursor. Doing this in the hotbar works fine, it's only in the upper half (upper 3/4) of the survival part of the creative inventory.

Steps to reproduce:

• Go into creative mode and get some same items into the hotbar
• Now go into the survival part of it and put some of those items in the top part and double click on it. (in the top part)
  > No stacking happens